Editorial

Multiple Primary Malignancies (MPM) was first described in 1879 by Billroth [1]. The
neoplasms may be limited to a single organ or may involve multiple separate anatomical organs.
The North American Association of Central Cancer Registries (NAACCR) classifies MPM into
two categories: (1) Synchronous, in which the cancers occur at the same time (the Surveillance
Epidemiology and End Results Programme (SEER) definition is within two months) and (2)
Metachronous, in which the cancers follow in sequence, that is, more than six months apart [1].
According to Warren Gates criteria a diagnosis of MPM require the following criterias to be
fulfilled (a) each tumor should present a definite picture of malignancy (b) each tumor should be
histologically distinct (c) the possibility that one is metastasis of the other must be excluded [2].
Meta–analyses show the frequency of second primary tumor (SPT) as 3-5%, third tumor (TT) as
0.5%, and fourth tumor, that is, quadrant tumor (QT), as 0.3%, in different organs and of different
histogenesis. Metachronous primary malignancies are becoming increasingly common because of
an increase in the number of elderly cancer survivors, greater awareness and improved diagnostic
modalities [3]. The exact pathophysiology for MPM remains unknown. However certain factors
have been postulated which includes the common carcinogen induced multiple cancers in an
exposed epithelial surface, called as “field-cancerization” as seen in head-neck tumors. In addition
other causative factors includes ionizing radiation, increased use of organ transplant, and the
increasing use of newer treatment modalities like hormonal manipulation, target therapies, genetic
manipulation, and immunomodulators [4]. In a study conducted by Chakrabarti et al. [5] it has
been reported that the over a period of 2 years, 12 cases of MPM were detected against a total of
1255 cases. Of these, five cases were synchronous malignancies and seven cases were metachronous.
Head and neck was the commonest site of index malignancies with seven cases followed by the
breast cancer with three cases and next gynaecological malignancies with two cases. Most common
sites for second primary malignancies (SPM) were head and neck with (four cases). Male to Female
ratio was 1:1.5 in the synchronous primary group and 1:1.3 in the metachronous group. Median age
of presentation of the primary tumour was 52 years and 6 months. The age range for the SPM was
17-72 years with the highest incidence in the 6th decade of life. Studies have reported that that the
relative risks of SPM ranges from 1.08 to 1.3. [6] SPM are often missed during follow-up and are
detected accidentally. The paucity of awareness about SPM has also prevented the formulation of
population-based screening protocol [7]. Multiple tumors that have been pathologically confirmed
at the time of presentation should be evaluated and staged as independent tumors. The treatment
plan should be decided after staging of both the primary and secondary tumors in view to attain
maximum clinical response. Proper counseling and patient’s understanding of magnitude of the
disease is paramount [8]. Operable synchronous SPM can be operated in a single setting with
minimal morbidity with better survival and is less taxing on the patient and his/her relative both
psychologically and financially. A regular follow-up on the patient by the clinician increases the
chances of early detection of metachronous SPM and the formulation of the treatment plan at the
earliest with better overall survival [9].
Availability of data regarding incidence of MPM, particularly those from developing countries
is very limited and hence further studies are needed. SEER is working in this direction with an
aim to define and develop appropriate and reliable criteria’s for synchronous and metachronous
cancers. It is imperative that patient with a primary malignant tumors should be thoroughly, closely,
and regularly followed. Genetic counseling, risk estimation, cancer screening and chemoprevention
must be emphasized. Appropriate cancer prevention strategy in with proper emphasis on
synchronous and metachronous cancer needs to be designed and incorporated in the National
Control Programme as multiple primary cancers have unique, biological behavior requiring specific
diagnostic and therapeutic interpretation.